Self-hardening furan resin compositions using a mixture of benzene sulfonyl chloride and trichloroacetic acid as catalysts



Patented Oct. 13, 1953 Alvin M. Edmunds and Lawrence F. Sonnabend,

Midland, Mich., assi cal Company, Midla elaware gnors to The Dow Chemind, Mich a. corporation of No Drawing. Application July 30, 1952, Serial No. 301,786

8 Claims.

hardening agent.

It is known that furfuryl alcohol and mixtures of furfuryl alcohol with a lesser amount, by weight, of one or more co-condensible compounds develop shrinkage cracks on standing. In some instances, the liquid resins develop a viscous outer layer, e. g. a crust or skin, in from 5 to 15 minutes after being treated with a catalyst and portant, the solid furan resins, as usually prepared, undergo a considerable shrinkage, usually in the order of 0.8 per cent or more of their for a month or longer, when used as mortar for the cementing together of bricks or tile.

prepared have been employed as mortar, e. g. for tile or brick used in lining chemical storage tanks.

the use of such cements.

It is an object of this invention to provide liquid, or plastic, self-hardening furan resin comor longer after being formed and thus permit ample time for shaping or applying the same; have Vie have found that mixtures of from 20 to per cent by weight of trichloroacetic acid and cent of benzene sulfonyl chloride are highly efiective as catalysts for causing the solidification and hardening of the aforementioned liquid fur-an resins at room temperature and that these catalyst mixtures differ from their individual ingredients and also from most catalysts previously known for the hardening of iuran resins in several important respects. The catalyst mixtures just mentioned exhibit a delay action, usually of from 1 to 4 hours at room temperature, after being admixed with a liquid furan resin, or a composition comprising such resin, before causing solidification of the resin. Accordingly, there is ample time for shaping, or otherwise working or applying, the resin compositions comprising such catalyst mixtures before solidification occurs. However, once the solidification reaction starts, the catalyst mixtures of the invention are highly effective in causing substantially complete polymerization in from 8 to 16 hours to form a hardened body less shrinkage on standing and has far less tendency to develop shrinkage cracks than is usual with iuran resin compositions which have been solidified with other catalysts heretofore used for the purpose. The individual ingredients oi the catalyst mixtures of the invention, i. e. benzene sulionyl chloride or trichloroacetic acid, do not possess such desirable characteristics. Instead, they each harden a iuran resin composition to form a solid body which undergoes more extensive shrinkage after becoming hardened than is obtained when similarly employing the catalyst mixtures of the invention.

The aforementioned catalytic mixtures of benzene sulfonyl chloride and. trichlorcacetic acid also have a desirable property, when added to a liquid furan resin, of causing substantially uniform solidification e d hardening of the entire body of resin without first forming a skin or crust at the surface of the composition. avoidance of skin formation facilitates use of the compositions, e. g. in making molded articles, or in coating solid bodies, etc.

We have further found that by admixing with the liquid iuran resin, powdered carbon, or powdered graphite, or a mixture of carbon and of from 80 to ill per graphite, and benzene sulfonyl chloride and 0131- ohloroacetic acid in the aforestated relative proportions, there are obtained cements which remain plastic for a considerable time, c. g, from 1 to 4. hours, and then solidify and harden in from 8 to 16 hours, at room temperature with formation of solid bodies having good dimensional stability. The linear shrinkage which the hardened cements of the invention undergo on standing for 1 year at room temperature does not exceed 0.6 per cent and usually is in the order of from 0.3 to 0.4 per cent. Such cements can be used to form laminated tank linings which do not develop cracks on standing, or they can be used as mortar for laying bricks or tile. The cements form a strong bond with bricks or tile, and are themselves strong and resistant to breakage. They are also resistant to chemical attack by acids, alkalies, and organic liquids such as benzene, toluene, carbon tetrachloride or acetone, etc. Accordingly, the cements are useful in lining vessels which are to contain acids, alkalies, or solvents. The invention pertains especially to such cements, but is not limited to them.

Any of the aforementioned liquid furan resins prepared from reactive starting material containing at least 50 per cent by weight of iurfuryl alcohol can be used as the resin ingredient of the compositions of the invention. A considerable number of such liquid furan resins are known and some of them are commercially available. Examples of such materials are the liquid polymers of iurfuryl alcohol, the liquid copolymers of iuriuryl alcohol and lesser amounts, by weight, of furfuraldehyde; liquid polymers prepared from solutions 01' resins such as polyvinyl butyral in a larger amount by weight of furfuryl alcohol; liquid polymers of mixtures of a major amount of furfuryl alcohol and a minor amount of formaldehyde; liquid polymers of mixtures of a major,

amount by weight of iurfuryl alcohol and minor amounts of iuriuraldehyde and phenol; and liquid polymers of mixtures of a major amount by weight of furfuryl alcohol and minor amounts of furfuraldehyde and acetone; etc. Such liquid furan resins, prepared from furfuryl alcohol as a principal starting material, are also known as iurfuryl alcohol resins.

Any of such liquid ruran resins canbe further polymerized to solidify and harden the same by mixing therewith minor amounts of benzene sulfonyl chloride and trichloroacetic acid in the aforementioned relative proportions. The benzene sulfonyl chloride and trichlcroacetic acid may be edded individually, or be premixed and added together. The catalyst mixture is usually employed in amount corresponding to from 10 to 25 per cent of the weight of the liquid 'furan resin which is to be solidified, but it may be used in smaller or larger amounts, e. g. in proportions corresponding to from I to 45 per cent of the weight of the resin liquid. Although any mixture of from 20 to 60 per cent by weight of trichloroacetic acid and from to 40 per cent benzene sulfonyl chloride is effective as a catalyst for hardening the resins to obtain solid bodies having, good dimensional stability, a saturated solution of trichloroacetic acid in benzene sulionyl chloride is readily prepared, is highly effective for the purpose, and is generally preferred. At room temperature, the saturated solution contains about 47.2 per cent by weight of trichloroacetic acid end about 52.8 per cent of benzene sulfonyl chloride.

As hereinbeiore mentioned, the catalyst mixtures of benzene sulfonyl chloride and trichloroacetic acid exhibit a delayed action which permits time for shaping or applying the resin com.- positions comprising the same. However, the reaction for solidification of the furan resins is exothermic and, once it starts, the catalytic mixtures of the invention cause it to occur quite rapidly. When the catalysts of the invention are added to a pint or more of an undiluted liquid furan resin, an extremely vigorous reaction sometimes occurs after the mixture has stood, e. g. for from 30 minutes to 3 hours or :thereabout. Occurrence of a violent reaction can be avoided either by spreading the catalyzed resin composition as a thin film so that heat generated by the reaction may rapidly be dissipated, or by admixing inert solids such as sand, pebbles, or powdered graphite, etc. with the liquid furan resins. The amount of solid inert material required to avoid occurrence of an excessively rapid reaction varies with changes in the kind and quantity of liquid iuran resin employed and the kind of solid material used as a diluent, or filler. Usually, we employ 50 per cent by weight or more, preferably from 4'7 to 62 per cent, of a finely divided solid, based on the combined weight of the same and the liquid furan resin, but the diluent can be used in smaller or larger propor- Other usual ingredients such as dyes, pigments, 1 perature to the desired viscosity usually in from or plasticizers, may be added to the compositions 20 to 48 hour When it is of from 500 to 4000 of the invention. The compositions should be centipoises viscosity at 25 (3., it is mixed with used within a short time, e. g. 1 to 3 hours or the other aforementioned ingredients and a furthereabout, after adding the benzene sulfonyl ther amount of the catalyst mixture to obtain a chloride and trichloroacetic acid. self-hardening resin composition.

The invention pertains especially to self-hard- The following examples describe ways in which ening cements prepared as just described, exthe invention has been practiced and illustrate cept that an inert finely divided solid, preferably certain of its advantages, but are not to be concarbon powder or powdered graphite, is used as strued as limiting its scope.

a filler and diluent for the resin. Carbon and graphite are particularly useful as the filler, since EXAMPLE 1 they, as well as the hardened furan resins, are To a mixture of 2 kilograms of ryl a ohol resistant to chemical attack by acids, alkalies, d 40 am of r a d hyd 63 rams f and solvents,i e by employing carbon r graphmaleic anhydride was added portionwise in 20 ite, or a mixture of the same as the filler there minutes With Stirringh m X u e Was Stirred fillers such as sand, or brick chips, silica pebbles, 0 10W bolllng materials, Water a d lm acted etc. Sand and brick chips or silica pebbles are furfur l l h l Th r m i product w a satisfactory as fillers when it is desired that the qu d fllmn resin hail/111g a Viscosity of 60 Centihardened cements be resistant to acids and solpoise-S at 25 C. A portion, i. 6. 43.5 parts by The plastic cements are most conveniently 50 parts of powdered graphite. The plastic the aforementioned liquid furan resins and then 40 for one hour or longer and thereafter hardened adding and mixing in the filler, the sever al ingrethroughout in a substantially uniform manner dients being used in the relative proportions here- P01 tions of the plastic cement were molded into inbefore given However, the ingredients can be test pieces wh eh harden d on sta d g t m admixed in other ways. For instance, the tritemperature n bout t hours- A bar of the mixed with the liquid furan resin to form the selfm x d nd a at i t v f 1 d y, 10 days, and hardening plastic em t, 30 days thereafter. It was found that the bar Although any of the aforementioned liquid had shrunk by 0.163 per cent of its original length furan resins, containing per cent by weight or 50 in the first day; by 0.2 2 per c nt of he or nal,

be used as the resin ingredients of the plastic ceoriginal length in 30 days From the decrease in ments, the amount of shrinkage which the freshamount of Shrlnkage Occurrmg p r d y, t 15 1y hardened cements undergo on standmg 5 d evident that at the end Of the 30 day pBIlOd the pendent, not only on the proportions of benzene shrinkage had almost eeased. S ven d ys a ter furan resins have viscosities in the order of from D1806 Weighed per t ss than t had be- 15 to 350 centipoises at 25 C. They may be used fore being immersed in the acid and that it had Another of the hardened test pieces was imand tested for tensile strength. It weighed 1.58 EXAMPLE 3 per cent more than before being immersed in the alkali solution and had a tensile strength greater 5 2232 SLSg'fgg fig f fiig sg i fiffig than 2000 pounds per Inch resin identical with that employed in Example For purpose of comparison, parts by weight yst in the proportions of the same liquid furan resin was admixed with given in Table II. Each cement was molded parts of mixture of 94 per cent of powdered into test pieces which hardened on standing Gabon and 6 per 9 of catalyst for the halidabout 4 hours at room temperature. A bar of enmg of fumn resms' catalyst was each cement was tested at intervals for shrinkture of per cent by weight benzene sulfonyl 10 age, as in Example Thirty days after chlor1de and 20 per centpara-toluene sulfonic coming hardened another test piece of each acid. The resultlng plastic cement was molded cement was used in determining its tensile mto test pleces whtch hardenedon standmg strength. Table 11 names the filler and catalyst room tempelfature m about 2 Seven days ingredients used in each cement and gives the after becoming hardened, the tensile strength of 15 proportions in parts by Weight of the several one of the test pleces was determlped and found starting materials. It gives the tensile strength, to be only 555 pounds per square inch cross secin pounds per Square inch of each hardened tion' cement and the per cent shrinkage of each EmMPLE 2 cement at stated times after it had hardened. In each of a series of experiments, one or both In the table, benzene sulfonyl chloride, trichloof the compounds, benzene sulfonyl chloride and roacetic acid, and para-toluene sulfonyl chloride trichloroacetic acid, were admixed with Alkor are abbreviated as PhSO2C1, C13AC, and

cement liquid (a commercially ava'lable liquid TOI-SOzCl, respectively.

Table II w Hardened cement V L d Filler Catalyst T 1 Percent shrinkage in- 1qu1 ensie restin, lsstreingth, 1 3 1 p s s. sq. in. 0

Kmd day days days year 013A 61. 42 T01-SO2CL 1, 203 102 387 422 632 150 294 307 413 39.42 Graphite. 39.5 do...

33. 3 Carbon. 33. 3 ..do

polyfurfuryl alcohol condensation resin) and the EXAMPLE 4 mixture was stirred together with powdered graphite to form a self -hardening plastic cement. The several ingredients were used in the relative proportions stated in the following table. Each cement was molded into test pieces which hardened, on standing at room temperature, in about 4 hours. The length of a hardened test bar of each cement was measured 24 hours after the cement had been prepared and also at the various times thereafter indicated in the table. The 30 cmonde parts of 1 i were admixed with 33.33 parts of the liquid resin of 15 by weight of each of the compounds, benzene sulwas Smrred parts of gramme powder The fonyl chloride and trichloroacetic acid in the r catalyst employed in each cement. It also gives pleces whmh hardened on standmg at room the per cent of its original length by which a perature in about 10 hours. The length of a test hardened bar had Shrunk on standing at room bar was measured 24 hours after it had hard- This example illustrates the effect, on the shrinkage of hardened cements of the invention, of a change in viscosity of a liquid furan resin 45 used in preparing the cements. The resin starting material was Permanite cement liquid (a commercial liquid furan resin) which had a viscosity of 15 centipoises at 25 C. In one experiment, 3.2 parts by weight of benzene sulfonyl temperature for the times stated in the table. fined and at intervals thereafter In another In the table, benzene sulfonyl chloride is abbrevi 6O experlment, a p 0f e iquid resln, havin ated as PhSOzCl and trichloroacetic acid is aba viscosity of 15 centipoises, was treated with breviated as ClsAC. 1.2 per cent of its weight of a mixture of 52.8

Table 1 Composition of Starting materials catalyst Percent shrinkage on standing- Run f g ow h- PhSOzCl, 0154.0, P1100101, 2$? 1 10 30 00 130 1 S 1te,pts. pts. pts. percent cent day days days days days days year p n mf -ff?! 40.1 55.0 4.0 0 0 0100 0410 0.433 0.435 0420 0430 0530 30.5 55.0 3.2 237 57.5 42.5 1 3 .337 .340 0 37 4 resulting plastic cement was molded into test per cent by weight benzene sulfonyl chloride and 47.

prepared in the first The cement was molded into test pieces which hardened on standing in about 8 hours. The length of a test bar was determined when it had hardened for 24 hours and at intervals thereafter. Table III identifies each experiment by giving the viscosity in centipoises at 25 (3., of the liquid resin used in making each cement. The table also gives the per cent of its original length by which a Table -III of liquid Run N resin, cps. 1O 15 at 25 C. 1 day 5 days days days R x x EXAMPLE 5 adding the catalyst. crust, formed thereon, ing the para-toluene sulfonyl chloride remained 40 i was stirred together with 58.66 parts of powdered 1 0 EXAMPLE 6 EXAMPLE 7 To 33.33 parts by weight of Permanite cement liquid (a liquid furan resin) having a viscosity of 46.4 centipoises at 25 0. there were added 4.27 parts of benzene sulfonyl chloride and 3.77 parts of trichloroacetic acid. The liquid mixture graphite. The plastic cement, thus formed, was

pieces were weighed and immersed for days in the following respective baths: (a) distilled water heated at 0., (b) an aqueous hydrochloric acid solution of 20 weight per cent concentration heated at C., and (c) an aqueous Table IV Results of immersion in- Percent shrinkage in" lday days 30 days 90 days 180days lyear fement 1120 at 100 C.

' EXAMPLE e A plastic cement was prepared by treating a liquid furan resin with approximately per cent of its weight of a hardening agent and stir ring 25 parts by weight of the resulting mixture together with 75 parts of a mixture of powdered coke,- sand, and silica pebbles of from about /4 to inch diameter. The liquid iuran resin was 7 one that had been prepared as described in Example 1. The hardening agent was a mixture of 52.8 per cent by weight oi benzene sulionyl chloride and 47.2 percent of trichloroacetic acid. The above-menioned solids consisted of 35 per cent by weight of powdered coke, 15 per cent sand, and 50 per cent silica pebbles. Approximately 200 pounds of the plastic cement was cast as a rectangular ring, or closed band, having wires embedded therein as reinforcing. The closed band had outside dimensions, for the rectangle, of 3 feet by 4 feet. The ring, or closed band, had a depth of 5 inches and a maximum thickness, from the inner to outer surfaces thereof, of approximately 6 inches. The cement ring or band, hardened on standing at room temperature for several hours. It was used as a segment or" the walls of apparatus for handling chemicals. Several days after the cement had hardened the apparatus was placed in service. It was employed under conditions such that part of the cement band was in contact with chlorine and aqueous hypochlorous acid and part of the band was in contact with an aqueous caustic soda solution of approximately 15 weight per cent concern tration, which solution was heated at a tempera--. ture of 85 C. After 3 months use of the apparatus under the conditions just described, it was removed from service and the cement band was examined. The cement band was not cracked, or otherwise damaged, and did not appear to have been corroded.

We claim:

1. A composition comprising a major amount by weight of a liquid furan resin, having at least 50 per cent by weight of iurfuryl alcohol chemically combined therein, and a minor amount of a mixture of from 80 to 40 per cent of benzene sulfonyl chloride and from to 60 per cent 01' trichloroacetic acid as a hardening'agent.

2. A composition, as claimed in claim 1, wherein the hardening agent is a substantially saturated solution of trichloroacetic acid in benzene sulionyl chloride.

3. A composition, as claimed in claim 1, wherein the liquid resin is a polymer of iurfuryl alcohol and the hardening agent is a substantially sat urated solution of. triohloroacetic acid in benzene sulionyl chloride.

i. A plastic cement capable of hardening on standing to form a solid body that undergoes not more than 0.6 per cent or linear shrinkage in one year after becoming hardened, which cement comprises from 33 to 45 per cent by weight of a liquid iuran resin from 4.7 to 62 per cent of at least one finely divided filler of the class consisting or carbon and graphite and from 5 to 15 per cent of a hardening agent, said liquid furan resin being one having at least 50 per cent by weight of furfuryl alcohol chemically combined therein and said hardening agent being a mixture of from to 40 per cent by weight of benzene sulionyl chloride and from 20 to 60v per cent or trichloroacetic acid.

5. A plastic cement, as claimed in claim 4; wherein the liquid iuran resin is a polymer of iurfuryl alcohol.

6. A plastic cement, as claimed in claim l, wherein the harden'ng agent is a substantially saturated solution or trichloroacetic acid in henzene sulfonyl chloride.

7. A plastic cement, as claimed in claim 4, wherein the liquid iuran resin is a condensation product of a mai or amount by weight of furruryl alcohol and minor amounts of formaldehyde and maleic anhydride, and. the hardening agent is a substantially saturated solution of trichloroacetic acid in benzene sulfonyl chloride.

8,. A method of solidifying and hardening liquid iuran resins, having at least 50 per cent by weight of furfuryl alcohol chemically combined therein, which comprises admixing with such resin a minor amount of a hardening agent consisting essentially of from 80 to 40 per cent by weight of benzene sulfonyl chloride and from 20 to 60 per cent of trichloroacetic acid.

ALVIN M. EDMUNDS. LAWRENCE F. SONNABEND.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A COMPOSITION COMPRISING A MAJOR AMOUNT BY WEIGHT OF A LIQUID FURAN RESIN, HAVING AT LEAST 50 PER CENT BY WEIGHT F FURFURY ALCOHOL CHEMICALLY COMBINED THEREIN, AND A MINOR AMOUNT OF A MIXTURE OF FROM 80 TO 40 PER CENT OF BENZENE SULFONYL CHLORIDE AND FROM 20 TO 60 PER CENT OF TRICHLOROACETIC ACID AS A HARDENING AGENT. 